When attempting to enable a newly configured T1 ISDN trunk, it fails to enable and the following error is reported:

ISDN signalling process configuration error (error_id = 29204)


When mixing configuration of T1 ISDN NFAS and T1 ISDN non-NFAS on the same system, a 29204 error occurs when the trunk of a different type is first enabled. The error parameter string reported is either 'Non NFAS trunk in NFAS system' or 'NFAS trunk in non-NFAS system'.

Resolving the problem

You are not able to configure both NFAS and non-NFAS trunks on the same voice adapter. Please set all trunks to be NFAS, or all trunks to be non-NFAS depending on your switch configuration.